Event-related brain potential (ERP) techniques provide unique information about component processes of human information processing. Individual ERP components represent electrophysiological manifestations of sensory and cognitive processing with millisecond temporal resolution. Furthermore these events reflect processes which precede or occur in the absence of overt behavioral output. We have used late ERP components, such as the P3 and the N400, to elucidate models of human information processing originally developed on the basis of behavioral data, such as the differentiation between automatic and controlled cognitive mechanisms. Over the past funding period, we have used ERP techniques to assess automatic processing of startling, distracting, and linguistic stimuli. We have found that automatic processes interact with controlled processes, implying that automatic and controlled processes share resources to some extent. We have also found that P3s elicited automatically show greater decline in elderly subjects than P3s elicited effortfully. Further, our data also indicate that the automatic N400 to semantically anomalous words is reduced and delayed in the normal elderly. Our specific aims for this continuation are to use ERPs: 1) To explore the interdependence of automatic and controlled processing and the allocation of resources between them when automatic processing is elicited by distractors. 2) To explore the Interdependence of automatic and controlled processing and the allocation of resources between them when automatic processing is elicited by speech. 3) To explore age-related changes in these processes. 4) To explore how these processes may be further altered with cognitive impairment.